The PC Geiger comprises a digital display that occupies one of the standard 5.25" drive bays on the front of your PC case, and a small card that plugs in to one of your PCI slots. Don't worry: the device simply monitors the PCI bus - it doesn't use an IRQ or any I/O space and nor does it require any operating system support or drivers. Think of this as an overgrown voltmeter. It will work without any operating system installed - in fact, it will even work without the CPU installed. The device provides a number of features: